The Data Bunker is a location in Epic Battle Fantasy 5 that was introduced in the v2 update. It is on the far left side of The Great Sea and somewhere south of Redpine Town. The Data Bunker contains simulations of foes and specific bosses from the four previous games, and can be accessed as soon as Poseidon is defeated.
The Data Bunker is a massive 3-story bunker built into the face of a cliff on one of the many islands of the Great Sea. The entrance is somewhat overgrown, with lots of plant life covering up parts of the entryway, but otherwise is in perfect condition. Amusingly, Lance initially assumes that it is a stronghold for a hostile force, similar to his Iron Fortress in No Man's Land.
True to its name, the Data Bunker stores information, carried on various computers and recording devices. However, it only seems to have recorded information about obscure Flash Games (no points for guessing which ones). The bottom floor also has some vegetable plants and a goat, ostensibly as the basis of a food source in case of a siege or global disaster.
The Data Bunker is populated by an assortment of people in charge of maintenance, running the simulations and keeping the place intact. There are also several references to other Flash games, movies, and internet memes on cork boards in one corner of the first and second floors.
The Data Bunker is notable for featuring some enemies and bosses from said games, with their appearance, stats and moveset largely unchanged from that of the original games, including resisting/ignoring status effects introduced in later games. The number of players that can be brought into battle is also limited (two for EBF1 and 2, and three for EBF3 and 4). This is done by picking the corresponding players in the party; if the player wants to bring different party members in they should rearrange the party's order.
The second floor allows fighting each of the included 8 bosses (2 per game) separately, always preceded by a wave of regular enemies. On the bottom floor are the 2-player and 3-player boss rushes, each consisting of 4 of the multi-wave battles fought previously, but without any interruptions between them.